1. Field of the Invention
The present invention relates to a method and an apparatus for an electrosurgical coagulation and cutting of regions of tissue or blood vessels over relatively large areas with temperature control.
2. Discussion of the Background
Surgical procedures and particularly electrosurgical procedures often require the complete cutoff of large regions of tissue, or the complete cutoff of the blood supply through a main artery before such surgery can be performed. A typical example is the requirement that the uterine artery be closed off before the uterus can be removed during a hysterectomy. The cutting off of the blood supply through the artery is accomplished by suture ligation, staples or clips or electrosurgical desiccation. Obviously, for large arteries, suture ligation is a difficult and long procedure which increases the time required for anesthesia resulting in an opportunity for complicating factors to arise. Aside from an increase in the length of time, there is an obvious increase in the expense of the procedure. Furthermore, when such arteries or vessels require their blood supply to be cut off during an emergency surgery, the amount of time to control the bleeding from the large vessel is more than just an expense or a complicating factor: it is a life-threatening period of time required before the actual surgery may be accomplished. Obviously, there is a need for an improved method for ligation and the cutting off of larger vessels.
Although the above example addresses the cutting off of a main artery, in many instances the blood supply needs to be cutoff to large regions of tissue containing many blood vessels and also in many instances the cutting off of the blood supply to these tissues is all that is required. In other words, in many applications, what is required is only the stopping of blood supply to a region of tissue containing many blood vessels.
In a similar manner, when cutting through large regions of tissue containing blood vessels, considerable time is expended ligating the individual blood vessels into tissue. There is a need for an improved method of cutting coagulating of such type of large regions of tissue.
One of the approaches in the electrosurgical procedure to reliably seal off large areas is the utilization of a device which can accomplish the cutoff of the blood supply through the main artery or a plurality of smaller vessels. Current electrosurgical devices face severe problems which either make their use inconvenient or severely limit their application or, in certain instances, entirely rule out the use of such electrosurgical devices. Prior art devices are inherently difficult to use over a large area or an extended linear region because it is difficult with current electrosurgical devices to produce coagulated tissue over such a large area or over such a long linear region. Furthermore, it is extremely difficult to know the degree of completion of coagulation because there is no feedback mechanism to determine when the coagulation is complete. Therefore, with the present electrosurgical devices it is entirely possible that the application of the device will have been stopped before completion of coagulation resulting in continued bleeding. It is equally possible that the device was applied for too long a time which, at best, is a waste of time and, at worst, could have caused other damage to adjacent tissue or could have burned the tissue intended to be coagulated, resulting in compromised sealing of tissue and the risk of continued bleeding.
Yet another difficulty with the present electrosurgical devices available for coagulation is the requirement for the use of multiple devices. That is, once coagulation has been completed, another device is necessary to cut the tissue.
Uniform coagulation over large areas of tissue using standard electrosurgical techniques is extremely difficult to achieve. This difficulty is due in part to the fact that it is not known how to determine the proper rate at which to apply energy or how to determine when the desired amount of coagulation has been achieved. If the energy is applied too rapidly, the superficial layers of tissue may desiccate too quickly and insulate the deeper tissues from further application of electrosurgical energy. If insufficient energy has been applied, the desired depth of penetration of the electrosurgical energy may never be achieved. The only feedback currently available to an operator of the prior art electrosurgical devices is the visible inspection of the surface of the tissue which is being coagulated or monitoring of the level of RF current. Surface inspection is no indication of any effect achieved in deeper layers of tissue. Similarly, a drop in RF current does not differentiate between the formation of an insulating superficial layer as complete desiccation. Thus, the application of electrosurgical procedures to cut off blood supply is a developed skill based upon experience which either requires separate training in this field or a stop-and-inspect procedure with even such procedure failing when the energy is applied too quickly because the deeper tissues may have become insulated from further heat application.
There thus exists a long-felt need for a rapid, efficient, safe and sure method and device for completely cutting off the blood supply through an artery for vessel and the subsequent cutting of the artery or vessel in order to prepare for a further surgical procedure.
A similar need exists for an efficient, safe and sure method and device for sealing or coagulating large areas of vascular tissue such as mesentery, bowel, mesoappendix, lung, fat tissue, lymph nodes, fallopian tubes, pedicles and the like.